SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '699947eebca1b1e349af6b10ae64d8f861989e18328a4c614152d7aa889a68da' 
  AND token = 'W1MRfjAEzCrk3iviRvGHKbq2748TBcwEG5ygQoSYak4=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00022

JSON explain

{
  "query_block": {
    "select_id": 1,
    "message": "no matching row in const table"
  }
}